Traditionally, the process of harvesting cotton included several steps. First, the cotton is gathered by a cotton harvester (called herein a “picker”) that traveled through the agricultural field separating the cotton bolls from the stalk and leaves of the cotton plant. The cotton bolls are then blown into a basket on the picker. Once the basket is full of loose cotton bolls, the picker either travels to a “module builder” which receives the loose cotton bolls, and compacts them to form a matted, compressed block or “module” of cotton, or alternatively loads the collected cotton bolls into a “boll buggy” (i.e. a wagon) that is configured to receive cotton bolls from the picker and transport them to the module builder. These modules are typically left in the field until a third vehicle can take them to a cotton gin for further processing.
In recent years this traditional process has been shortened. Instead of picking the cotton bolls, loading a boll buggy and taking it to a module builder, the step of picking and module building are combined. The picking and module building are performed simultaneously by a self-propelled picker/module builder. This picker/module builder travels through the field picking cotton and simultaneously building a module from that cotton.
Using this new process (and equipment), a farmer can eliminate the need for a boll buggy and separate module builder. Instead, the picker/module builder creates modules as it moves through the field harvesting cotton, leaving the modules in place in the field as they are created, much as hay balers leave bales of hay behind them in the field. The picker/module builder can travel much further before it needs to stop and unload, since it packs the cotton as it picks and therefore creates a much larger payload in the same space.
The picker/module builder includes a header which harvests the cotton, strips it of leaf and stalk, and blows the cotton bolls into a chamber on the back of the picker/module builder. This chamber combines a basketlike structure with a compactor frame. The picker/module builder periodically cycles the compactor frame up and down to successively packed layers of loose cotton bolls.
The header which compels the cotton bolls into the chamber does not automatically distribute the cotton evenly. Typically, when the picker/module builder is empty, cotton bolls are blown into the rear of the chamber. As the chamber fills, cotton bolls are blown into the front of the chamber. In order to create a module of relatively constant density, the cotton bolls must be distributed within the chamber underneath the compactor frame. To do this, the compactor frame is equipped with several augers oriented fore-and-aft with respect to the picker/module builder. When the augers are driven in one direction, they pull cotton from the front of the vehicle to the rear of the vehicle underneath the compactor frame. When driven in the opposite direction, the augers will pull cotton from the rear of the vehicle to the front of the vehicle. In this manner, the picker/module builder distributes the cotton evenly as it compacts successive layers of cotton blown into the chamber.
In order to determine what direction to drive the augers, the picker/module builder has several sensors that detect the relative orientation of the compactor frame when it is lowered into contact with the cotton in the chamber. If more cotton has been blown and then piled up in the rear of the chamber, the front part of the compactor frame will be pressed down farther than the rear part of the compactor frame. Sensors are provided on the picker/module builder to determine the relative orientation of the compactor frame. The sensors detect whether the compactor frame is higher in the front than in the rear (indicating that too much cotton is being piled up in the front of the chamber and must be shifted to the rear by the augers), or higher in the rear at than in the front (indicating that too much cotton is being piled up in the rear of the chamber and must be shifted to the front by the augers.
The sensors must detect relatively small tilt angles of the compactor frame with respect to the chamber. Providing accurate measurements of small angles requires careful maintenance of the sensors. If they are bumped or twisted, if their electronic circuits drift in calibration, or if their linkages to the compactor frame are bent or otherwise shifted from their design positions, the signals provided by the position sensors can be in error. When the sensors provide erroneous signals, controller 106 does not drive the augers in the proper direction, or for the proper length of time and the cotton is not level.
What is needed, therefore, is a system and method for quickly calibrating the module builder's, compactor's and auger's operation by calibrating the sensors that detect the position of the augers and compactor frame of the module builder with respect to the compactor chamber. It is an object of this invention to provide such a system and method.